Disposable thermometer structure

ABSTRACT

A simple thermometer structure having an indicating rod adapted to extend therefrom and to move inwardly of a tubular housing with increasing temperature. The thermometer is set for operation by an internal latching arrangement operable by manual withdrawal of the indicating rod from the housing at the time of use of the thermometer.

0 United States Patent 1 011 3,713,416 Volk [4 1 Jan. 30, 1973 [54]DISPOSABLE THERMOMETER [56] References Cited STRUCTURE UNITED STATESPATENTS 1 lnvemori Anllmny Volk, 173 East Syracuse 3,090,235 5/1963Houser ..73/3S8 Turlock. Calif 95380 3,548,780 12/1970 Kliewer ..73/35822 F1 d: A 'l l 72 l 1 W 9 Primary Examiner-Louis R. Prince [21] Appl.No.: 240,365 Assistant Examiner-Denis E. Corr Related Us. ApplicationData Att0rney-Alvm E. Hendncson et al. [63] Continuation-impart of Ser.No. 122,604, March I, B T A T 197] A simple thermometer structure havingan indicating 52 U.S.Cl ..ll6/ll4.5,73/358 adapted exend f f move [51]Int Cl 601' 11/06 wardly of a tubular housing with increasing tempera-[58] Field of Search 73/358; 116/ 145; 99/192 TT; ture. The thermometer15 set for operation by an internal latching arrangement operable bymanual withdrawal of the indicating rod from the housing at the time ofuse of the thermometer.

4 Claims, 5 Drawing Figures PATENIEDJ/m 30 I975 .FIG.4

DISPOSABLE THERMOMETER STRUCTURE This is a continuation-in-part of myprior copending U.S. patent application Ser. No. 122,604 filed Mar. 1,1972 for Disposable Cooking Thermometer.

BACKGROUND OF INVENTION There have been developed a variety of differentdisposable cooking thermometers primarily designed for use with meat orfowl and intended to be inserted in the meat or fowl prior to sale tothe consumer. Such thermometers are intended for but a single use andnormally incorporate some type of physically movable element andtemperature sensing means cooperating therewith such that a variablevisually observable portion of the element is indicative of thetemperature of the thermometer.

Disposable cooking thermometers may, for example, be inserted inturkeys, roasts, or the like, prior to freezing and shipping of same forretail sales. The disposable thermometer of my above-noted copendingpatent application has proven highly successful in this respect as wellas with fresh meat and fowl and the present invention is particularlydirected to an improvement thereon. This prior thermometer has theindicating rod so formed that it is adapted to be bent over and latchedto the top of the tubular housing when the thermometer is originallyinserted in the fowl or meat. Although this structure is highlysatisfactory in operation, it does require the physical latching of theindicator rod at the time of manufacture or insertion and this involvesa certain amount of time and expense.

It will be appreciated that disposable cooking thermometers of the typeherein contemplated must be quite inexpensive inasmuch as they actuallycomprise a throw-away item. Any additional cost in manufacture orinsertion of thermometers of this type is to be avoided.

The present' invention incorporates an internal latching arrangementwhereby the indicator rod is retained substantially entirely within thehousing until the thermometer is actually to be used. The user thenmanually latches or sets the thermometer to extend the indicator rodtherefrom so that during cooking of a turkey, for example, the rodslowly moves inwardly of the housing to indicate the degree of coolingof the turkey. This then reduces the cost of a disposable cookingthermometer of this type and simplifies the storage and transportationof a frozen food containing disposable thermometers.

SUMMARY OF INVENTION The thermometer of the present invention comprisesa tubular housing preferably having a closed pointed end for insertioninto meat, fowl, or the like, with an indicating rod slidably engagingthe housing for extension from the outer end thereof. Within the housinga spring urges the indicator rod inwardly of the housing to press theinner rodend against a fusable metal disposed in a longitudinal bore inthe forward end of the housing. The inner end of the rod is dimensionedto slide into the bore and as the metal softens within increasingtemperature, theindicator rod is then urged further into the housing sothat the extent of the indicator rod outside the housing is anindication of the temperature of the thermometer. To this extent thepresent invention is the same as the invention of my above-notedcopending patent application.

The present invention provides a latching structure internally of thethermometer housing with the indicator rod being divided into two parts;the upper or outer portion of the rod fitting into the adjacent end ofthe inner portion of the rodunder normalinoperative condition. In orderto set the thermometer for operation, the exposed end of the indicatorrod is drawn outwardly of the housing to compress the spring in thehousing and to lock the two portions of the rod together in extendedposition. More specifically, the present invention provides in. thelatching structure notedabove an axial bore in the end of the innerportion of the rod. The outer portion of the rod has a pivotably mountedlatch at the inner end thereof which is originally pivoted to liealongside the rod as both are inserted in the bore in the inner rodportion. A spring is disposed about the upper portion of the rod and isretained in the housing to initially extend into the above-noted bore.As the outer portion of the rod is manually withdrawn from the housing,the spring is compressed and, as the pivot latch emerges from the borein the inner portion of the rod, the latch is pivoted by the spring toextend laterally of the outer portion of the rod across the bore so thatthe outer portion of the rod can no longer enter the bore. In thisposition the two portions of the indicator rod are extended to full rodlength with the outer portion of the rod then extending a predetermineddistance from the housing. A flexible loop on the indicator rodexteriorly of the housing provides ready gripping means for withdrawingthe rod from the housing to set or latch the thermometer and preferablythe housing itself has lateral extensions so that an operator may pressagainst same as he withdraws the rod from the housing.

DESCRIPTION OF FIGURES The present invention is' illustrated in theaccompanying drawing wherein:

FIG. 1 is a perspective view of a disposable cooking thermometer inaccordance with the present invention;

FIG. 2 is a central longitudinal sectional view of the thermometer ofFIG. 1 in uncooked or unlatched position;

FIG. 3 is a perspective view of the upper portion of an indicating rodas may be employed in the thermometer of this invention;

FIG. 4 is a sectional view in the same plane as FIG. 2 and illustratingthe thermometer in latched or set position ready for indicating thetemperature of meat, fowl or the like, in which the thermometer may bedisposed; v

and

FIG. 5 is a sectional view illustrating the relative position ofelements at an intermediate temperature being indicated by thethermometer.

DESCRIPTION OF PREFERRED EMBODIMENT Considering now a preferredembodiment of the present invention and referring to the drawing, therewill be seen to be illustrated a thermometer having a small elongatedtubular housing 11 which preferably The housing defines an internalcylindrical opening 14 extending from the back of the housing to thefront where the small bore 13 commences and within this opening 14 thereis slidably disposed two-part indicator rod 16. The innermost portion ofthis rod may be denominated as a slide 17 having an upper portion 18slidably engaging the interior walls of the housing and a dependingaxial extension 19 of reduced diameter adapted to fit within the housingbore 13. This axial'extension 19 of the slide element 17 is formed withlongitudinal grooves about same to provide a predetermined crosssectional area for flow of softened temperature sensing metal, asfurther described below. Within the housing bore 13 there is provided amaterial 21 that becomes plastic or liquid at a predeterminedtemperature. This material may, for example, be comprised as Cerro metalor any of a variety of metal alloys including, for example, Woods metal,bismuth, tin, and the like. The material 21 has a predeterminedsoftening temperature and thus, as this temperature is approached andreached, the extension 19 is forced into the bore 13 to press the metal21 therein up and out of the bore about this extension 19.

The upper and lower portions of the indicator rod 16 are adapted totelescope and to this end there is provided an axial bore 22 in theupper end of the slide member 17. The upper rod portion 23 may becylindrical or may be formed as a flat bar, as indicated in FIG. 3. Atthe bottom of this upper rod 23 there is provided a pivotally mountedlatch 24. In practice the rod 23 and latch 24 may be formed as a singlepiece of lightweight plastic having a limited flexibility with theconnection of rod and latch merely comprising a necked-down or very thinportion of the rod, as illustrated at 26 of FIG. 3. This then provides aflexibility of connection, such that the plate-like latch element 24 maypivot at the connection, as indicated by the arrows in FIG. 3. Thislatch element 24 will thus be seen to have an illustrated positionextending laterally of the rod 23 at the bottom end thereof or a pivotedposition wherein the latch is aligned with the rod lying along a sidethereof at the inner end of the rod. In this second latch position therod and latch are dimensioned to fit within the end depression 22 of theslide member 17, as illustrated in FIG. 2. Other latch connection ispossible; however, the one described is quite simple, inexpensive andeffective.

There is provided a compression spring 27 about the rod 23. A collar 28closes the outer end of the housing opening 14 and may be provided withan annual ring to snap into a groove in the housing for retaining thecollar in position. The collar 28 has an axial slot therethrough forextension of the upper rod 23, as illustrated in FIG. 2, and the spring27 bears against the underside of the collar 28 to retain the springwithin the housing.

In the normal or storage position of the thermometer hereof, the innerend of the rod 23 and the latch 24 are inserted in the bore 22 in theend of the slide member 17, as illustrated in FIG. 2.-The spring 27 isdisposed about the rod 23 beneath the collar 28 and may also extend intothe bore 22, again as illustrated in FIG. 2. It is provided by thepresent invention that the thermometer hereof shall be set or latched bydrawing the rod 23 outwardly of the housing 11 and to this end there isprovided means for gripping the outer end of the rod 23. This grippingmeans 31 may be provided as a flexible loop of plastic thread or thelike connected to the outer end of the rod 23 or possibly some type ofinsignia cap or the like connected to the rod. By this means a user ofthe thermometer may grip the loop or the like 31 and pull the rod 23outwardly of the housing to compress the spring 27 against the collar28.

Provision is also made for preventing the slide member 17 from movingoutward of the housing with the rod 23 and means to this end may, forexample, comprise a longitudinal extension 29 on the collar 28 extendingalong a side of the housing opening 14 to engage the upper end of theslide member 17. With the rod 23 having a rectangular configuration, asillustrated, and the latch member 24 pivoting against the broad sidethereof, this collar extension 29 is disposed on the side of the collaradjacent the narrow side of the axial slot through the collar in orderto be disposed alongside the latch 24. This then prevents any possibleengagement of latch plate 24 and collar extension 29 which mightconceivably prevent the latch from fully swinging into perpendicularrelationship with the rod 23. Because of the very minute dimensions ofthe interior elements of the present invention, care must be taken toensure clearance for the latch plate 24.

Under the, circumstances wherein a cylindrical rod 23 is employed,alternative provision for preventing the slide member 17 from movingupwardly in the housing is preferably employed. Such mens might, forexample, comprise a small lateral extension or ring on the lower part ofthe upper portion 18 of the slide member which would be slipped over asmall inner protuberance of the housing extending into the opening 14therein so that the slide member would be free to move inwardly of thehousing but not outwardly thereof. It will be appreciated that a varietyof different means may be employed in connection with maintaining theslide member 17 in position during latching of the thermometer hereof.

The thermometer housing 11 may be additionally provided with a laterallyextending flange 32 about the outer end of the housing to serve as apurchase when latching the thermometer. Additionally, the housing isprovided with laterally extending barbs or the like 33, as illustratedin FIG. 1, for the purpose of securing the housing in inserted positionin meat, fowl, or the like.

Considering now operation of the present invention, it is first notedthat the illustration of FIG. 2 shows the thermometer in normal orunactuated position with the indicator rod substantially entirely withinthe housing. It is noted that in this illustration the loop 31 is shownextending upwardly from the end of the indicator rod for clarity ofillustration but, in practice, this loop would normally lie flat on theflange 32. This then provides the present thermometer with asufficiently flat outer or end surface that it does not provide anyproblem to the packaging of meat, fowl, or the lie, when the thermometeris inserted in same. In order to set or latch the present thermometer incondition for use, a housewife, for example, merely draws the upperportion 23 of the indicator rod out of the housing by slipping a fingerthrough the loop 31 and pulling. The flange 32 provides a purchase sothat other fingers or thumb of the hand may be placed thereagainst whilepulling the loop 31. As the upper rod portion 23 is withdrawn from thehousing, the inner end of the rod 23 with the latch 24 thereon moves outof the axial bore 22 in the lower portion 17 of the rod. This compressesthe spring 27 and, as the rod 23 clears the end of the member 17, thespring bearing on the latch 24 pivots the latch into the positionillustrated in FIGS. 3 and 4. As will be seen in FIG. 4 the length ofthe latch element 24 is greater than the diameter or cross sectionaldimension of the bore 22 in the element 17 and thus, with the latchpivoted to extend laterally across the inner end of the rod 23, this rodcan no longer enter the bore 22. This condition is illustrated in FIG. 4wherein the thermometer may be considered as set or latched with the twoportions of the indicator rod extending full length so as to extend theouter portion of the rod a prescribed distance from the outer end of thehousing. In this condition the spring 27 is compressed to urge the slidemember 17 inwardly of the housing and thus to press the end of the axialextension 19 of this element into the metal 21. As the temperature ofthe thermometer approaches and reaches the softening temperature of themetal 21, this axial extension 19 will then be forced into the metal soas to move into the bore 13 while the metal is squeezed about thisextension and up into the large housing opening 14, as illustrated inFIG. 5.

It will be seen that the present invention, as described above, providesan improved disposable thermometer structure. The degree of cooking ofmeat, fowl, or the like, in which the present invention may be inserted,is accomplished in the same manner as the thermometer of my above-notedcopending patent application. The present invention does, however,advantageously provide an improved structure wherein the indicator rodof the thermometer is normally maintained substantially within thehousing thereof. This simplifies the assembly of the thermometers totherefore effect a reduction in cost of manufacture and furthermoreprovide certain advantages in the use of the thermometer.

It is not intended to limit the present invention to the details ofdescription or illustration, for it will be apparent to those skilled inthe art that various modifications may be made within the scope of thisinvention.

What is claimed is:

l. in a disposable cooking thermometer having an elongated hollowhousing with resilient means for urging an indicator rod inwardly of thehousing against a thermally plastic material, the improvementcomprissaid indicator rod being formed of separate upper and loweraxially aligned sections with a first section fitting partially withinan axial depression in the other section in a first retracted positionand latching means holding said sections substantially apart against theforce of said resilient means in a second extended position.

2. The thermometer of claim 1 further defined by the first section ofsaid indicator rod having an outer end thereof extending from saidhousing,

said resilient means comprising a compression spring about the firstsection of said indicator rod, and

said latch comprising a plate pivotally connected to an inner end of thefirst section of said indicator rod for insertion in the depression inthe second section of said indicator rod and having a sufficient lengthto bridge said depression under the urging of said spring in saidextended position of the indicating rod.

3. The thermometer of claim 2 further defined by at least the firstsection of said indicator rod being formed of limitedly flexible plasticmaterial and said latch being integral therewith and said pivotalconnection being a reduced cross section of this same material.

4. A disposable cooking thermometer comprising a hollow tubular housinghaving a small axial bore internally of an inner end thereof,

a solid thermoplastic material disposed in said housing bore with suchmaterial having the property of melting at a predetermined temperature,

a slide member having an axial bore in an outer end thereof disposed insaid housing and having an axial extension bearing on said thermoplasticmaterial with said extension being adapted to slidably fit said bore ofsaid housing with a predetermined clearance,

collar means closing an outer end of said housing,

an indicator rod disposed axially of said housing through said collarmeans and disposed substantially entirely within the housing,

a spring disposed between said collar means and slide member about saidindicator rod, and

latch means pivotally mounted on an inner end of said indicator rod forinsertion into the axial bore of said slide member in a normal positionof the rod and pivotal by compression of said spring for dispositionacross said bore upon retraction of the rod from the housing into anoperating position of the rod with such rod extension from the housing.

1. In a disposable cooking thermometer having an elongated hollowhousing with resilient means for urging an indicator rod inwardly of thehousing against a thermally plastic material, the improvement comprisingsaid indicator rod being formed of separate upper and lower axiallyaligned sections with a first section fitting partially within an axialdepression in the other section in a first retracted position andlatching means holding said sections substantially apart against theforce of said resilient means in a second extended position.
 1. In adisposable cooking thermometer having an elongated hollow housing withresilient means for urging an indicator rod inwardly of the housingagainst a thermally plastic material, the improvement comprising saidindicator rod being formed of separate upper and lower axially alignedsections with a first section fitting partially within an axialdepression in the other section in a first retracted position andlatching means holding said sections substantially apart against theforce of said resilient means in a second extended position.
 2. Thethermometer of claim 1 further defined by the first section of saidindicator rod having an outer end thereof extending from said housing,said resilient means comprising a compression spring about the firstsection of said indicator rod, and said latch comprising a platepivotally connected to an inner end of the first section of saidindicator rod for insertion in the depression in the second section ofsaid indicator rod and having a sufficient length to bridge saiddepression under the urging of said spring in said extended position ofthe indicating rod.
 3. The thermometer of claim 2 further defined by atleast the first section of said indicator rod being formed of limitedlyflexible plastic material and said latch being integral therewith andsaid pivotal connection being a reduced cross section of this samematerial.